With the “Prevent booking gaps” setting, your clients can only book at the start of your working hours, or directly before or after an existing appointment. This way, your appointments follow each other without empty gaps in your schedule.
This setting applies to all your 1-on-1 services. It doesn’t affect group services.
Step-by-step guide:
Go to your Admin page.
Click on Settings>Scheduling rules
Scroll down to the Prevent booking gaps option.
Turn on the Enabled toggle.
Click Save when you're done.